This is topic of great interest for a number of reasons. Mike, Jon and I have several papers in this basic direction (with hopefully more coming soon). Probably the most relevant of our paper is “Distance Measures for Dynamic Citation Networks” which we published in Physica A back in late-2010. For those who might be interested – a copy of our paper (with James H. Fowler) is available on SSRN and on ArXiv.

Dr. Peter Erdi is one of the leading scholars studying the path of innovation as revealed through the U.S. Patent Citation network. Above is his most recent talk – Prediction of Emerging Technologies Based on Analysis of the U.S. Patent Citation Network

From the Abstract: “The taxonomy visualization and validation (TV) tool introduced in this paper supports the semi-automatic validation and optimization of organizational schemas such as file directories, classification hierarchies, taxonomies, or other structures imposed on a data set for organization, access, and naming. By showing the “goodness of fit” for a schema and the potentially millions of entities it organizes, the TV tool eases the identification and reclassification of misclassified information entities, the identification of classes that grow too large, the evaluation of the size and homogeneity of existing classes, the examination of the “well-formedness” of an organizational schema, and more.”

Michael Bommarito, Daniel Martin Katz & Jonathan Zelner, Law as a Seamless Web? Comparing Various Network Representations of the United States Supreme Court Corpus (1791-2005) in Proceedings of the 12th International Conference on Artificial Intelligence and Law (ICAIL 2009 - UAB Barcelona) < SSRN >